In response to the demands of consumers who are driven both by ever-escalating fuel prices and the dire consequences of global warming, the automobile industry is starting to embrace the need for ultra-low emission, high efficiency cars. While some within the industry are attempting to achieve these goals by engineering more efficient internal combustion engines, others are incorporating hybrid or all-electric drive trains into their vehicle line-ups.
Irrespective of whether an electric vehicle (EV) uses a hybrid or an all-electric drive train, the battery pack employed in such a car presents the vehicle's design team and manufacturer with a variety of challenges. For example, the size of the battery pack affects the vehicle's weight, performance, driving range, available passenger cabin space and cost. Battery performance is another characteristic in which there are numerous trade-offs, such as those between power density, charge rate, life time, degradation rate, battery stability and inherent battery safety. Other battery pack design factors include cost, material recyclability, and battery pack thermal management requirements.
Given the size of the battery pack used in a typical EV and the fact that such packs often use a large number of small form factor batteries, it is critical to reduce both component cost and assembly time in order to lower the overall cost of the vehicle. One approach to simplifying battery pack design is to align the batteries such that all of the electrical connections can be made at one end of each of the cells using a plurality of bus bars and high current interconnects. This approach has the added benefit of allowing either an air-based or a liquid coolant-based cooling system to be thermally coupled to the opposite end portions of each of the batteries, thereby allowing the efficient removal of the heat generated by the cells during operation.
Accordingly, what is needed is a battery pack design that simplifies a battery pack configuration in which all electrical connections are made at one end of each of the batteries. The present invention provides such a design.